The present invention relates to a rotary screw blancher, and in particular, a blancher for processing multiple products a day that is easy to clean between product runs.
In mass processing of food product, food product is often heated by cooking or blanching the food product in a food processing apparatus having a tank holding a heat transfer medium into which the food product is immersed. After cooking or blanching of the food product occurs, the food product is cooled or chilled by immersing the food product in a cool transfer medium so that the food product may be packaged, stored and/or shipped. In some known systems, a rotary drum blancher or a rotary screw blancher is used to first cook or blanch the food product and the food product is discharged onto a belt or other type of conveyor and advanced to a rotary cooler to reduce the food product temperature to an acceptable temperature. In another known system, a single compact apparatus to heat and cool the food product in continuous flow is used, that is a combination cooker-cooler.
In a rotary drum blancher, food product is introduced into an inlet end of an elongate drum, which is rotatably mounted in a generally cylindrical, open-top tank. The tank is fitted with a cover for minimizing heat loss and for enclosing the drum for safety reasons, and which can be opened for maintenance and cleaning. The drum includes an auger therein for advancing food product from the inlet end of the drum to an outlet end of the drum and through the heat transfer medium. The drum includes a structural frame with perforated skin panels, some of which may be pivotally attached to the frame to serve as access doors.
In a rotary screw blancher, food product is introduced into an inlet end of a generally cylindrical, open-top tank. A rotatable auger is mounted within the tank for advancing food product from the inlet end to an outlet end of the tank and through a heat transfer medium. The tank is fitted with a cover for minimizing heat loss and for enclosing the auger for safety reasons, and which can be opened for maintenance and cleaning.
The rotary blancher is used to cook a variety of food products, including pasta, rice, vegetables, dry beans, pouched meat and pouched sauces. Cleanliness is a concern in the food processing industry, and strict hygienic standards and inspections are observed throughout the industry for machinery that comes in contact with food for human consumption. Many facilities will process small batches of a variety of products in a single day or shift, which requires cleaning of the rotary blancher, and in particular the drum, between product runs. It is necessary for rotary blanchers to provide access for cleaning sprays to all joints and cavities within the drum where contaminant accumulation may occur. In current rotary drum blanchers, it is necessary to remove perforated skin panels from the drum frame or reposition access doors of the drum to perform the necessary cleaning. Such actions require high levels of labor and machine down time.
One solution is use of a rotary screw blancher, which is easier to clean because the blancher lacks a drum and has higher food product capacity than similarly sized rotary drum blanchers because food product can run at deeper depths. However, the auger causes more damage to food product as compared to rotary drum blanchers, especially if food product is caught in clearance gaps between the auger and the tank, the increased processing depth causes more friction between the food product and the auger flights, as well as the tank wall, and the increased depth causes increased temperature gradients in the process water.